Condensed Combining Financial Information of L-3 Communications and Its Subsidiaries - Condensed Combining Balance Sheets (Detail) (USD $) In Millions, unless otherwise specified	Mar. 29, 2013	Dec. 31, 2012	Mar. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 276	$ 349	$ 493	$ 764
Billed receivables, net	1,108	968
Contracts in process	2,748	2,652
Other current assets	558	602
Total current assets	4,690	4,571
Goodwill	7,720	7,744
Other assets	1,470	1,511
Total assets	13,880	13,826
Current liabilities	2,567	2,597
Other long-term liabilities	2,096	2,061
Long-term debt	3,629	3,629
Total liabilities	8,292	8,287
L-3 shareholders' equity	5,513	5,463
Noncontrolling interests	75	76
Total equity	5,588	5,539	6,837	6,724
Total liabilities and equity	13,880	13,826
L-3 Communications Holdings, Inc. [Member]
Current assets:
Investment in and amounts due from consolidated subsidiaries	6,202	6,152
Total assets	6,202	6,152
Long-term debt	689	689
Total liabilities	689	689
L-3 shareholders' equity	5,513	5,463
Total equity	5,513	5,463
Total liabilities and equity	6,202	6,152
L-3 Communications Corporation's [Member]
Current assets:
Cash and cash equivalents	66	246	290	644
Billed receivables, net	383	290
Contracts in process	1,031	945
Other current assets	258	248
Total current assets	1,738	1,729
Goodwill	2,246	1,993
Other assets	754	734
Investment in and amounts due from consolidated subsidiaries	7,107	7,204
Total assets	11,845	11,660
Current liabilities	916	823
Other long-term liabilities	1,787	1,745
Long-term debt	3,629	3,629
Total liabilities	6,332	6,197
L-3 shareholders' equity	5,513	5,463
Total equity	5,513	5,463
Total liabilities and equity	11,845	11,660
Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents			7
Billed receivables, net	508	441
Contracts in process	1,320	1,351
Other current assets	118	163
Total current assets	1,946	1,955
Goodwill	4,333	4,586
Other assets	523	565
Investment in and amounts due from consolidated subsidiaries	3,463	3,326
Total assets	10,265	10,432
Current liabilities	1,019	1,255
Other long-term liabilities	206	210
Total liabilities	1,225	1,465
L-3 shareholders' equity	9,040	8,967
Total equity	9,040	8,967
Total liabilities and equity	10,265	10,432
Non-Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	223	242	213	222
Billed receivables, net	217	237
Contracts in process	397	356
Other current assets	182	191
Total current assets	1,019	1,026
Goodwill	1,141	1,165
Other assets	193	212
Investment in and amounts due from consolidated subsidiaries		43
Total assets	2,353	2,446
Current liabilities	645	658
Amounts due to consolidated subsidiaries	268
Other long-term liabilities	103	106
Total liabilities	1,016	764
L-3 shareholders' equity	1,337	1,682
Total equity	1,337	1,682
Total liabilities and equity	2,353	2,446
Eliminations [Member]
Current assets:
Cash and cash equivalents	(13)	(139)	(17)	(102)
Total current assets	(13)	(139)
Investment in and amounts due from consolidated subsidiaries	(16,772)	(16,725)
Total assets	(16,785)	(16,864)
Current liabilities	(13)	(139)
Amounts due to consolidated subsidiaries	(268)
Long-term debt	(689)	(689)
Total liabilities	(970)	(828)
L-3 shareholders' equity	(15,890)	(16,112)
Noncontrolling interests	75	76
Total equity	(15,815)	(16,036)
Total liabilities and equity	$ (16,785)	$ (16,864)